A Brief Legal Analysis of Authentication of Documents using Blockchain Technology

Blokusign is a new application for enabling the legal validity and management of agreements. It offers a major advantage over existing e-signature solutions by allowing users to independently verify the existence, timing, and authenticity of their signed documents.

Other e-signature solutions issue only a transaction receipt that lists signers’ IP addresses, email addresses, date, and time. These receipts are easily altered and have no security mechanisms. Furthermore, these receipts are centrally stored and managed, which can lead to doubts about their authenticity. Records that are under the control of an authority can be tampered.

How It Works

Blokusign connects the document to an address and a hash of the signed document on a public blockchain. A cryptographic hash is the ‘fingerprint’ of a file — changing the file, to any degree, will completely alter the hash. Because of this property, hashes can be used to demonstrate the authenticity of a document, even when it has been copied and stored under someone else’s control. Similarly, linking the document to an address, and supporting the transaction with cryptographic assurances of validity, helps ensure that the person creating the record has the authority to do so. Finally, by encoding a hash of the document, users can easily prove that their locally-held copies are correct, while at the same time creating an incontrovertible timestamp of the agreement.

To be clear, Blokusign does not store the signed document itself on a blockchain, as that would be an inefficient and costly use of precious block space. Instead, Blokusign’s solution is simple and elegant: a hash of the signed document is stored on a public blockchain and provided as part of the transaction receipt. Users are free to use their own document storage methods, whether local storage, cloud services like AWS or Dropbox, or Blokusign’s storage service (to be provided in a future release).

If the user ever needs to check whether a document is authentic, the user merely needs to compare the hash ‘fingerprint’ of the document to the one stored on the blockchain. If the two values are identical, then the document has not been altered. Users can also do the reverse: because each hash uniquely identifies documents, hashes can also be used to locate particular files with ease.

Blokusign’s solution is far simpler and more reliable than existing methods, which may either check metadata (which may be altered) or rely on centralized e-signature solutions to verify it from their own storage.

Amy Wan

Amy Wan is Co-Founder and CEO of Sagewise, a dispute resolution infrastructure for smart contracts. Previously, she was a Partner at a boutique securities law firm and General Counsel at a real estate crowdfunding platform. Amy is also the founder and co-organizer of Legal Hackers LA, which programs around the intersection of law and technology; was named one of the one of ten women to watch in legal technology by the American Bar Association Journal in 2014; and was nominated as a Finalist for the Corporate Counsel of the Year Award 2015 by LA Business Journal.
Amy has also worked in international regulatory and trade policy at the U.S. Department of Commerce, and was a Presidential Management Fellow at the U.S. Department of State and U.S. Department of Transportation. She holds an LL.M. in Public International Law from the London School of Economics and Political Science, a JD from the University of Southern California Gould School of Law, and a BA in Biological Sciences from the University of Southern California.
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